1. Field of the Invention
The present description relates to a thin film transistor (TFT) array panel for a liquid crystal display (LCD) or an organic light emitting display (OLED), and a method for manufacturing the same.
2. Description of the Related Art
Liquid crystal displays (LCDs) are a popular type of flat panel display. An LCD includes a liquid crystal (LC) layer positioned between two panels provided with field-generating electrodes. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer that determines orientations of LC molecules in the LC layer to adjust polarization of incident light.
A common type of LCD includes two panels provided with field-generating electrodes respectively, wherein one panel has a plurality of pixel electrodes in a matrix and the other panel has a common electrode covering the entire surface of the panel.
The LCD displays images by applying a different voltage to each pixel electrode. The TFTs, which have three terminals to switch voltages applied to the pixel electrodes, are connected with the pixel electrodes, and gate lines transmitting signals to control the TFTs and data lines transmitting voltages applied to the pixel electrodes are formed on a TFT array panel.
The TFT is applied to an active matrix organic light emitting display and operates as a switching element to control respective light emitting elements.
Molybdenum (Mo), chromium (Cr), and titanium (Ti) are the materials conventionally used for forming the gate lines of a TFT array panel.
When a size of an LCD is increased, a material having low resistivity is required since the lengths of the gate and data lines are increased. Accordingly, there are limitations when applying Mo, Cr, and Ti to a large size LCD.
Copper (Cu) is a well known material used as a substitute for Mo, Cr, and Ti because it has low resistivity. However, bad adhesiveness of Cu with a glass substrate is problemsome when applying Cu to a gate line. Therefore, there is a need for a material having low resistivity and sufficient adhesive properties to be used for the gate lines of the TFT and signal lines.